1. Technical Field
The present invention relates to a communication circuit, a physical quantity measurement device, an electronic apparatus, a moving object, a communication method, and so on.
2. Related Art
In recent years, devices having an interface compliant with the I2C bus communication protocol using the I2C (a registered trademark) using a master-slave system have become widely used. The I2C bus is composed of two serial buses formed of one clock signal line and one data signal line, and by connecting one master device and a plurality of slave devices to these signal lines, a high-speed data communication system can be established at low cost. In, for example, JP-A-2012-32262, there is described the fact that the I2C bus can be adopted as a bus for a sensing device.
In the I2C bus communication protocol, the master device has the initiative of the data communication, and performs the data communication with one of the slave devices connected to the I2C bus. Since the master device is not allowed to perform the data communication with a plurality of slave devices at the same time, a command signal output by the master device includes an address value (ID) called a slave address for identifying each of the slave devices. Then, when the slave device having the own ID equal to the slave address included in the command signal output by the master device sends an ACK signal (ACKnowledgement signal) back to the master device, the data communication is thereafter performed between the master device and that slave device.
Here, JP-A-2009-105731 discloses a data communication system including a communication control device to thereby make it possible to connect a plurality of slave devices having the same address values while using the I2C bus communication protocol.
Here, in order to perform the reliable communication, it is preferable to perform a propriety determination of the command signal from the master device, namely to determine whether or not the command signal includes an error. Further, if there is an error in the command signal, it is preferable for the slave device to immediately notify the master device in order to realize a high-speed data communication system. This is because if the master device immediately receives the error notification, a response such as retransmission becomes possible. However, in the related-art transmission compliant with the I2C bus communication protocol, the slave device is not allowed to notify the master device of the occurrence of the error unless the slave device newly receives the command signal for determining presence or absence of the error from the master device.